Regulator for generators



-' v A. F. BROTZ 'REGULAT'O'R FOR GENERATORS. v

"Filed Aug. 4.1 1921 ATTORNEY at Wltaye Cbil Patented Nov. 6,

or KOHLEB, WISCONSIN, A

.. I 1,472,788 UNITEDTSTAVTES PATENT OFFICE.

airron FRANK nno'ra'or, KOHLEB, -WISCONSIN,. assronon 'ro xonpnn comm,

CORPORATION OF WISCONSIN.

REGULATOR FOB GENERATORS.

Application filed August 4, 1921. Serial No. 489,880.

To all whom it may concern:

Be it known that I, ANTON FRANKBRo'rz, a citizen of the United States, and resident of Kohler, in the county of Sheboygan and I State of Wisconsin, have inventednew and useful Improvements in Regulators for Generators, of which the following is a description, reference being had to the accompanying drawings, which are a part of this specification.

This invention relates to regulators for generators designed to correspondingly vary the speed of the generator with the variations in the load to maintain an ap- 1 proximately constant voltage. 7

While the invention is not confined to any particular adaptation, it is especially applicable to internal combustion, engine driven farm lighting and power plants and serves 2 to approximately proportion the fuel consumption to the actual'load.

The present invention constitutes an improvement on, or a development of, the invention covered by my ap lication for genverator regulators, Serial 0. 463,432, filed April 21, 1921, and provides it with a means 2 for avoiding the excessive voltage that may occur upon suddenly changing from full load to minimum load. Under these condi- 10 tions it may not be practicable to effect the corresponding reduction in speed in time to prevent a momentarily dangerous rise in voltage.

With this end in view the present invention provides, in addition to the regulating means for varying the speed of the generator with the load, an automatically operated switch for introducing resistance in series with the shunt field when said regulating means reaches the end of its movement.

Instead of regulating the voltage by maintaining a constant generator speed, a series field windin is used to buck or oppose the shunt fie d winding and thereby weaken the. field strength as the load increases, while automatic means simultaneously opens the throttle of the engine to increase its speed. a j These two influences are so related that 6 they maintain the voltage a proximately constant, but at times when t e reduction in speed of the enerator lags-behind the reduction in loai-the automatic throttleoperating means, after completing its 0 eration of closing the thrott e, is capab e of of few turns of lar further movement in the same direction to operate a switch for weakening the shunt field of the generator by introducing resistance in series therewith and thus development of an excessive voltage.

avoid the With the above and other objects in view, the invention consists in the regulator for generators as herein claimed and all equivalents.

Referring to the accompanying drawin s,

in which like characters of reference in 1- Gate the same parts in different views:

Fig. 1 is a diagram of a regulator for generators embodying this invention;

Fig. 2 is a detail view of the throttle actuating and resistance controlling solenoid employed therein; and,

switch.

Fig. 3 is a view showing the closed position' of the resistance short .1

circuitin C In these drawings 10 indicates a generator driven by an internal combustion engine,

the throttle valve 11 of which is by a solenoid having windings with the generator wmdings, as will be decontrolled connected scribed. The generator as shown is of the shunt type and supplies the .mains 12 com taining lamps 13 or other translating devices. The shunt field winding generator is opposed by a bucking series 14: of the old winding 15 which'becomes stronger as the load on the mains increases and thereby opposes a greater'influenc'e to the shunt field to weaken the field strength. At the same time a series coil 16, also in the load circuit and strengthened by the increasing load, opposes to a greater extent the influence of a shunt or voltage coil 17 to efiect a further opening movement of the throttle valve of the engine to increase the speed of the engine.

As an example of a solenoid adaptedfor this purpose there is shown in Fig. 2 a so lenoid 18 including the voltage coil 17 of many turns of fine wire which may being connected in parallel with the shunt field 14;, as shown, and the current or series coil 16 v enclosed within an iron casing 19 havmg an iron head 20. The

solenoid core 21 movable within the brass Hol core 22 is ivotally connected to the shorter arm of a ell crank lever 23'fulcrumed on a brass cap 24. The core is pressed ulpr wardly b a coil s ring 25 and is centra y' positione within t e core 22 and permitted i It.

to sway with the movments of the bell crank by having brass cross pins 26 through it slidably bearing on the core tube.

A link 27 connects the longer arm of the bell crank lever 23 with the arm of throttle 11 so that in the extreme upper position of the core, as when the, generator is not operating and the coils are therefore not en ergized, the throttle is held in a partly closed position a.

\Vhen the generator is started with a m nimum load or no load on the service mains, the series coil 16 opposes the voltage coil 17 only slightly or not at all, and the core will be drawn to a lower position against the pressure of spring 25 and will move the throttle to a position 0 practically closing the intake manifold of the engine, so that the engine operates at a min1mum speed under which the generator develops the line voltage. As the load is increased the generator field is weakened, as above mentioned, the influence of the bucking current coil or series coil 16 becomes greater, tending to neutralize the influence of the voltage coil 17 and permit-ting the spring 25 to lift the core and move the throttle toward its open position Z), thus increasing the supply of fuel to the engine to increase its speed corresponding with the increase in the load.

The full open position I) of the throttle 11 is attained under the condition of maximum load and should for any reason the current strength be increased beyond this, as upon the occurrence of an overload, the further movement of the throttle toward the a position resulting therefrom will tend to slow down the engine. Also, with automatic starting control, the partially closed position (L of the throttle for starting prevents the engine from racing before connecting the generator with the load. as is done when it is started with the throttle in full open position.

The proportioning of the field windings of the generator and of the coils of the solenoid and of the throttle and its operating means is made to compensate for a change in load by a change in speed without a material change in voltage developed by the generator. The weakening of the generator field by the bucking coil serves to facilitate the increasing of the speed of the engine caused at the. same time by the bucking influence of the series coil of the solenoid opening the throttle, and this bucking field winding exaggerates the speed variation characteristic of the generator for constant voltage conditions so that the desired object is accomplished of materially reducing fuel consumption to correspond with a reduction of load.

As so far described the present invention is l ke that covered by my co-pending appli cation referred to and for the increased regulation a resistance 30 is connected in series with the shunt field winding 14 of the generator and wires 31 and 82 connect the ends of this resistance with switch contacts 33 and 3% respectively of a resistance short circuiting switch operated by the solenoid core. This switch in detail is shown in Figs. 2 and 3 as embodied in the solenoid. A cleat 34: is fastened to the solenoid head 36 and has a tubular guide 37 of insulating material seated in an opening therethrough. The guide 37 is flanged and the flange forms a seat for the coil spring 25, previously referred to. A stem 38 slidably passes through the tubular guide 37 and has an insulating tip 39 secured on its upper end and a contact member 33 secured on its lower end. A coil spring 41 surrounds the stem and is confined between the insulating tip 39 and the end of guide 37 and serves to normally hold .the contact member 33 in contact with the cleat or contact 34 to short circuit the regulating resistance 30 in the shunt field circuit. The throttle 11 in its 0 position engages a stop 42 and the connection between the bell crank 23 and the link 27 is of a yielding nature that will permit of a further downward movement of the solenoid core 21 after the throttle has reached the closed position 0. This further movement will bring the solenoid core into engagement with the insulating tip 39 so that the stem 38 is depressed against the action of its spring 41, thus opening contacts 83 and 34 to include the regulating resistance 30 in the shunt field circuit.

By means of this improvement the momentary rise in voltage when the load is suddenly reduced from full load to minimum load is prevented, the sudden weakening of the bucking current coil 16 accompanied by a slight strengthening of the voltage coil 17 being sufficient to cause the core 21 to move beyond the position for closed throttle and into the position shown in Fig. 2 for opening the short circuiting switch around the regulating resistance 30, and thus including this resistance in the shunt field winding to weaken the fields and check the rise in voltage. Such tendency to abnormal voltage is only momentary and as soon as the speed of the generator has reduced to correspond with the new throttle position. the normal conditions are restored, spring 25 lifting the solenoid core out of engagement with the switch stem so that the short circuiting switch is again closed and normal regulation is resumed.

What I claim as new and desire to secure by Letters Patent is:

1. In combination with a ated throttle-control for of a gas engine according to the load on the mains of a gas-engine-driven generator plant, a switch opened by the solenoid core solenoid-opervarying the speed by movement thereof beyond the position in which it closes the throttle,"and a regulating resistance in series with the shunt field winding of the generator and normally short circuited by the switch,

, 2. In a gas-engine-operated generating system, the combination with means for automatically varying the speed of the engine with the load, of a switch operated by said means when it reaches the end of its speed reducing movement, and a resistance inserted in the shunt field circuit by the operation of said switch.

3. In an internal -combustionenginedriven generator system, means for varying the speed of the engine with the load comprising an engine throttle sensitive tovariations of the load, a bucking series field for varying the field strength of the generator, a switch operated by said means at the end of its throttle closing movement, and a shunt field resistance controlled by said switch.

4. A generator having an armature and a shunt field, service mains connected across the armature, a series field opposed to the shunt field, an'engine having driving connection with the generator, means dependent on the current flow through the service mains for varying the position of the throttle of the engine, and means for avoidin an excessive voltage upon a sudden change rem full load to minimum load conditions comprising a switch operated by said means after closing the throttle, and a shunt field resistance controlled by said switch.

5. In a generating plant, an internalcombustion-engine-driven generator having a shunt field, a series field forming a bucking current coil in series with the service mains and opposing noid having a coil in series with the service mains and having its core connected with the throttle of the internal combustion engine for opening said throttle as the load on the service mains increases, a switch operated by the solenoid core at the end of the throttle closing movement thereof, and a shunt field resistance controlled by the switch.

6. In a generating plant, an internal-combustion-engine-driven generator having a shunt field, a series field comprising a bucking current coil in series with the service mains and opposing the shunt field to weaken the field as the load on the service mains increases, a solenoid having its core connected with the throttle of the internal combustion engine, a voltage coil on the solenoid tending to move the throttle'to its closed position, a current'coil on the solenoid in series with the service mains and opposing the voltage coil for moving the throttle toward its open position as the load on the service mainsl increases, a spring-closed switch embodied in the solenoid and engaged and opened by the solenoid core by a further movement of the core after the throttle is closed, and a shunt field resistance controlled by the switch.

In testimony whereof I afiix my signature,

ANTON FRANK BROTZ.

the shunt field, a sole 

